1. Field of Invention
The present invention relates to recumbent vehicles and particularly to three wheel pedalled vehicles wherein the vehicle includes a single rear drive wheel and two front steerable wheels.
2. Description of the Prior Art
Recumbent vehicles are constructed so that the rider is in a natural seated position with a feet forward orientation, usually with a back rest and in a nearly horizontal position. The advantages of this position over the conventional bicycle upright position are widely known and include a more comfortable riding position, greater power applied to the pedals, and improved safety in collisions due to the feet forward position. In addition, the lower riding position provides a low center of gravity for greater stability and reduced wind resistance.
Various patents have described recumbent vehicles including U.S. Pat. Nos. 4,659,098; 4,283,070; 2,147,732; and 4,878,684. Although these describe vehicles providing recumbent position, they are two wheel vehicles which are unstable at low speeds and difficult to ride particularly during starting and stopping and typically have long wheel bases and poor maneuverability.
Three wheel recumbent vehicles provide all the advantages associated with the recumbent position and in addition provide a totally stable vehicle which can start and stop without the rider putting his feet on the ground, and require no special skills or training to learn to ride.
Prior art patents which describe three wheel recumbent vehicles include U.S. Pat. Nos. 3,981,516; 4,432,561; and 3,753,577. These disclose vehicles with three wheels however with two wheels in the back and one steerable wheel in the front. This configuration resembles the traditional tricycle with the rider seated in a relatively high, upright position resulting in higher wind resistance and poor performance. In addition, these have typically been heavy weight vehicles with additional complexity of driving two rear wheels.
Other examples of three wheel recumbent vehicles describe vehicles with a single rear wheel including U.S. Pat. Nos. 3,913,929; 4,373,740; 4,410,198; 4,456,277; 4,548,421; and 4,993,733 and foreign patent SU 1406024. These vehicles have several drawbacks as follows.
U.S. Pat. No. 3,913,929 discloses a three wheel recumbent vehicle with a single rear wheel driven by two chains and two steerable front wheels which turn in the same plane. The long wheel base reduces maneuverability and does not allow short radius turns. In addition, the two front wheels turning in the same plane results in sliding of the wheels and higher rolling resistance. The rider support seat described does not provide a substantial back rest resulting in loss of effective leverage for pedalling.
U.S. Pat. No. 4,373,740 discloses a complex and heavy frame and a high seat position which increases wind resistance. Also described is a steering column which could interfere with rider movement and a long wheel base resulting in poor maneuverability. In addition, the vehicle does not provide lateral support for the rider during a turn.
U.S. Pat. No. 4,410,198 discloses a single tube main frame which is heavy due to bending loads, a steering column interfering with rider motion, and a single joy stick controller. The single tube frame is in bending and therefore heavy. The vehicle described does not address the steering mechanism required to eliminate sliding of the front wheels and does not provide lateral support for the rider during a turn. U.S. Pat. No. 4,456,277 discloses a front wheel drive recumbent vehicle with a complex and heavy frame. The additional complexity of front wheel drive requires a differential and front disc brake. The vehicle described has a long wheel base for poor maneuverability and employs a standard Ackerman steering arrangement.
U.S. Pat. No. 4,548,421 also discloses a vehicle with a single tube frame which is heavy and does not address the complex bending moments. It also discloses a steering column which interferes with rider movements and does not provide a steering mechanism for true rolling at the front wheels. In addition, the rider is not secured in the vehicle for lateral support during turning.
U.S. Pat. No. 4,993,733 discloses yet another vehicle with a single tube frame which is heavy and does not address the complex bending moments adequately. In addition, the long wheel base reduces maneuverability and the wheels turn in the same plane and so do not address the rolling condition at the road. Also the rider is not secured in the vehicle for lateral support during turning. Foreign Pat. SU 1406024 discloses a folding recumbent vehicle with a single tube frame and cantilever front wheel supports. The single tube frame with hinge points and cantilever members are in bending and therefore heavy.
Generally, the vehicles described are heavy, with a long wheel base and poor maneuverability. In addition, none of these address the issue of lateral support for the rider during turning. Other disadvantages which have been noted include rider discomfort with steering sensitivity due to excessive chatter or jittering of the wheels due to slight rider motions of the steering bar. Yet another disadvantage of the prior art includes a safety issue concerning visibility while riding among traffic due to the particularly low riding position.
It would be advantageous to provide a recumbent vehicle with a lightweight yet stiff frame and substantially foreshortened wheel base enabling a short turning radius which provides a safe, comfortable vehicle with lateral support for the rider during turning. It would also be advantageous to provide a vehicle with sensitivity adjustment in the steering mechanism to solve the problem of jittering of the steering wheels and a steering mechanism which independently controlled each wheel to a different angle thereby eliminating sliding of the wheels and reducing rolling friction. It would also be advantageous to provide a solution to the visibility problem in order to provide improved safety while riding in urban situations. The usefullness of such an invention is evidenced by greatly enhanced personal commuting and touring, particularly for long distance rides. The present invention relates to such a recumbent vehicle.